The present invention relates to the packaging of products in bags made from a puncture-resistant flexible film. More particularly, the present invention relates to a patch bag, as well as processes of making patch bags.
Patch bags are known for the packaging of bone-in meat products, such as whole bone-in pork loins, etc. The patch reduces the likelihood of film puncture from protruding bones. Many of the patch bags which have been in commercial use for some time have two patches, i.e., one on each side of the lay-flat bag. In this manner, coverage is enhanced over a single patch which covers only one side of the bag, as the two-patch embodiment provides patch coverage on more than just one side of the bag.
However, providing patch coverage on both lay-flat sides of the bag has generally required adhering separate patches on each side of a lay-flat tubing. The adhesion of a patch to each side of the bag has involved a complex series of steps: (a) at intervals, adhering a first set of patches to a first side of a lay-flat tubing film; (b) winding up the resulting laminated article; (c) unwinding the laminated article; and, at the same regular intervals, (d) adhering a second set of patches to the other side of the tubing preferably while taking care to ensure that the second set of patches is aligned with the first set of patches. In this manner, a bag having patches on both lay-flat sides is prepared.
It would be desirable to provide a patch bag having patch coverage on both lay-flat sides, without having to apply separate patches in the relatively complex manner described above. It would also be desirable to provide a patch bag having one patch which extends to cover more than 50 percent of the distance around the bag, while covering a side-edge or bottom-edge of the bag.
The present invention is directed to a patch bag, and processes of making patch bags, which provide a single patch covering at least a portion (preferably more than 50% across the width) of each of the lay-flat sides of the bag, while avoiding having to apply two separate patches. Moreover, the patch covers a side-edge and/or bottom-edge of the bag. In this manner, coverage can be provided on two different sides of the bag, without having to apply a plurality of patches to the bag film in the making of a single patch bag. This, in turn, avoids the need to register the position of patches so that they are aligned with each other.
As a first aspect, the present invention is directed to a patch bag, comprising a bag having an open top, a bottom seal, and a side-seal at a first side edge of the bag, and a patch which covers a seamless (i.e., folded, unsealed) second side edge of the bag and at least a portion of both a first lay-flat side of the bag and a second lay-flat side of the bag. Preferably, the bag comprises a heat-shrinkable film and the patch comprises a heat-shrinkable film. Preferably, the patch is adhered to an outside surface of the bag.
Preferably, the patch has a width of from about 20 to 200 percent, based on the width of the bag, more preferably, from about 55 to 200 percent; still more preferably, from about 60 to 190 percent.
Preferably, the bag comprises a first biaxially-oriented, heat-shrinkable film comprising an outside abuse layer, a core O2-barrier layer, and an inside-sealant layer. Preferably, the outside abuse layer of the first film comprises at least one member selected from the group consisting of ethylene/alpha-olefin copolymer having a density of from about 0.85 to 0.95 g/cc, propylene/ethylene copolymer, polyamide, ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, and ethylene/butyl acrylate copolymer. Preferably, the core O2-barrier layer of the first film comprises at least one member selected from the group consisting of ethylene/vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, and polyacrylonitrile. Preferably, the inside-sealant layer of the first film comprises at least one member selected from the group consisting of thermoplastic polyolefin, thermoplastic polyamide, thermoplastic polyester, and thermoplastic polyvinyl chloride.
Preferably, the patch comprises a second biaxially-oriented, heat-shrinkable film. Preferably, the second biaxially-oriented, heat-shrinkable film comprises at least one member selected from the group consisting of ethylene/alpha-olefin copolymer having a density of from about 0.85 to 0.95 g/cc, propylene/ethylene copolymer, polyamide, ethylene/vinyl acetate copolymer, ethylene/methyl acrylate copolymer, and ethylene/butyl acrylate copolymer.
Preferably, the bag comprises a first film and the patch comprises a second film, the side-seal is through the first film but not through the second film, and the end-seal is through the first film but not through the second film. Preferably, the first film has a thickness of from about 1.5 to 5 mils, and comprises an O2-barrier layer and a layer comprising ethylene/alpha-olefin copolymer having a density of from about 0.85 to 0.95 g/cc. Preferably, the second film has a thickness of from about 2 to 8 mils, and comprises ethylene/alpha-olefin copolymer having a density of from about 0.85 to 0.95 g/cc.
As a second aspect, the present invention pertains to a process of making a patch bag, comprising: (A) adhering a patch film to an elongate flat film having a first side edge and a second side edge, whereby a laminated film article is produced; (B) folding the laminated film article along its length, Whereby a folded, laminated article is formed which has a seamless folded side edge along a fold line thereof; (C) making a first seal by sealing the folded, laminated article to itself, the first seal being along a length of the folded, laminated article, the first seal being spaced from the folded side edge of the folded, laminated article; (D) making a second seal by sealing the folded, laminated article to itself by sealing across the folded, laminated article, whereby a sealed laminated article is formed; and (E) cutting across and through the sealed laminated article below the second seal, whereby an L-seal patch bag is produced. Preferably, the patch is adhered to an outside surface of a bag formed from the sealing of the elongate flat film to itself. Preferably, the patch has a width of from about 20 to 200 percent, based on the width of the L-seal patch bag.
Preferably, the elongate flat film has a substantially uniform width, and the folding is carried out at a centerline running a length of the elongate flat film, so that the first side edge of the elongate flat film and the second side edge of the elongate flat film are placed next to one another, whereby a folded, laminated article is formed which has a seamless folded edge formed along the centerline of the elongate flat film. Preferably, the elongate flat film is prepared by slitting a tubing along its length whereby a slit tubing is produced, followed by opening the slit tubing up to produce the elongate flat film.
Preferably, a plurality of discrete film patches are adhered to the elongate flat film, the film patches being adhered across the elongate flat film at intervals to form the laminated film article, the patches covering intervals of a seamless folded edge of the elongate flat film.
The bag and the patch film composition and characteristics are preferably as set forth according to the first aspect of the present invention.
As a third aspect, the present invention pertains to a process of making a patch bag, comprising: (A) adhering a patch film to an elongate flat film having a first side edge and a second side edge, Whereby a laminated film article is produced; (B) folding the laminated film article along its length, whereby a folded, laminated article is formed which has a seamless folded edge along a fold line thereof, (C) sealing the folded, laminated article to itself by making a plurality of side-seals across the folded, laminated article; (D) cutting across the folded, laminated film outward of the side-seals, whereby a side-seal patch bag is produced. The folding, sealing, and cutting are carried out so that the patch film covers a seamless bottom edge of the side-seal patch bag.
Preferably, the flat film has a substantially uniform width. Preferably, the folding is carried out at a centerline running a length of the elongate flat film, so that the first side edge of the elongate flat film and the second side edge of the elongate flat film are placed next to one another. Preferably, the seamless folded edge is covered by the patch.
Preferably, a plurality of discrete film patches are adhered to the elongate flat film, the film patches being adhered across the elongate flat film at intervals relative to one another to form the laminated film article. Preferably, each of the patches covers the centerline running a length of the elongate flat film. Preferably, the elongate flat film is prepared by slitting a tubing along its length whereby a slit tubing is produced, followed by opening the slit tubing up to result in the elongate flat film Preferably, the patch has a length of from about 20 to 200 percent, based on the length of the patch bag; more preferably, from about 20 to 180 percent. Preferably, the elongate flat film comprises a first biaxially-oriented, heat-shrinkable film comprising an outside abuse layer, a core O2-barrier layer, and an inside-sealant layer, and the patch comprises a second biaxially-oriented, heat-shrinkable film. Preferably, the bag and the patch film composition and characteristics are preferably as set forth according to the first aspect of the present invention.
According to an alternative preferred embodiment of the third aspect of the present invention, the elongate flat film has a substantially uniform width, and the folding is carried out along a line parallel to a machine direction of the elongate flat film, but offset from a centerline by a distance of from about 0.1 inch to 2 inches, Whereby a folded, laminated article is formed, the folded, laminated article having a seamless folded edge on a first side edge thereof, and offset lips on a second side edge thereof Preferably, the process further comprises puncturing a protruding offset lip, so that a hole is formed in the protruding offset lip.
As a fourth aspect, the present invention pertains to a patch bag, comprising: (A) a bag having an open top, a bottom seal, a first lay-flat side, a second lay-flat side, a seamless first side edge, and a seamless second side edge; (B) a patch covering: (i) across an entirety of a width of the first lay-flat side of the bag, (ii) the seamless first side edge; and (ii) the seamless second side edge; and (C) a backseamed seal in the second lay-flat side of the bag, the backseamed seal running a length of the bag.
As a fifth aspect, the present invention pertains to a process of making a patch bag, comprising: (A) adhering a patch film to an elongate flat film having a first side edge and a second side edge, whereby a laminated film article is produced, (B) folding the laminated film article at two separate folds along its length, so that a folded, laminated article is formed which has a first lay-flat side, two seamless side edges, and a second lay-flat side containing two overlapping film regions; (C) making a first seal by sealing the overlapping film regions to one another along the length of the folded, laminated article; (D) making a second seal by sealing the folded, laminated article to itself by sealing across an entirety of the folded, laminated article, whereby a sealed laminated article is formed; and (E) cutting across and through the sealed laminated article below the second seal, whereby a backseamed patch bag is produced.
As a sixth aspect, the present invention pertains to a patch bag, comprising: (A) a bag having an open top, a first side-seal, a second side-seal, and a seamless bottom edge; and (B) a single patch which covers the seamless bottom edge of the bag, at least a portion of an outside surface of a first lay-flat side of the bag, and at least a portion of an outside surface of a second lay-flat side of the bag, the single patch having a length of from about 101 to 200 percent of a length of the bag. Preferably, the single patch has a length of from about 105 to 200 percent of the length of the bag; more preferably, from about 110 to 200 percent; still more preferably, from about 110 to 180 percent; yet still more preferably, from about 110 to 170 percent.
As a seventh aspect, the present invention pertains to a process of making a patch bag, comprising: (A) adhering a patch film to an elongate flat film which has a first side edge and a second side edge, whereby a laminated film article is produced; (B) folding the laminated film article transverse to its length, the folding being in a region of the laminated film article in which the patch film is adhered to the elongate flat film, whereby a folded, laminated article is formed which has a seamless folded transverse bottom edge; (C) sealing the folded, laminated article to itself by making a first seal along the first side edge and a second seal along the second side edge, whereby the elongated flat film becomes a sealed article; and (D) cutting across and through the laminated film article at a location above the bottom edge, whereby a side-seal patch bag is produced, and wherein the folding, sealing, and cutting are carried out so that the patch film covers a seamless bottom edge of the folded elongate film, and the patch film is adhered to the outside surface of the sealed article.